Well drilling bits



Jan. 6, 1959 Q s 2,867,413

WELL DRILLING BITS Filed Dec 19, 1955 1 INVENTOR- OIe, K. Olse n ATTORNEY United States Patent WELL DRILLING BITS Ole K. Olsen, Garland, Tex.

Application December 19, 1955, Serial No. 553,832

8 Claims. (Cl. 255-61) This invention relates to new and useful improvements in 'well drilling bits, and particularly to drag blade type bits.

One object of the invention is to provide a new and improved drag bit which is designed for use in relatively soft and crumbly formations for rapid penetration of the formations.

A particular object of the invention is to provide a new and improved drill bit having a plurality of uniformly spaced radially disposed pilot cutting blades for cutting the center of the hole being bored by the bit, and which is provided with cutting fingers adjacent and spaced outwardly from the outer edge of each of the drag blades for cutting the major volume of the formation being dug through, the pointed tips of the fingers facilitating penetration of the formations with a reduced weight applied to the bit.

A further object of the invention is to provide a bit of the character described wherein the outer edges of the cutting fingers are provided with vertical sizing and shaping surfaces for shaping and sizing the hole being bored to assure a uniform hole of substantially reamed diameter and of a high degree of straightness.

Another object of the invention is to provide a drill bit of the character described having a large water flow course extending therethrough for washing the cuttings out of the hole rapidly.

Still another object of the invention is to provide a bit of the character described having hard-surfaced cutting edges providing for long life of the bit.

An important object of the invention is to provide a bit of the character described having the vertically disposed fingers positioned above the cutting surfaces of the drag blades forming the pilot hole whereby the formation cut by the fingers is cut toward the center of the hole and the cuttings are forced inwardly away from the outer periphery of the bore hole by the cutting fingers.

Additional objects and advantages of the invention will be readily apparent from the reading of the following description of a device constructed in accordance with the invention, and reference to the accompanying drawings thereof, wherein:

Figure 1 is a side elevation of a drill bit constructed in accordance with the invention,

Figure 2 is a bottom end view of the drill bit of Figure 1, and,

Figure 3 is a view taken on the line 33 of Figure 2,

and showing a portion of the bit in cross-section.

In the drawings, the numeral designates a drill bit body having an axial bore or flow course 11 extending therethrough. The body is provided at its upper end with 3:

external tapered pipe threads 12 by means of which the body may be connected to the lower end of a string of drilling pipe or the like. Below the threaded section, the exterior of the body is convexly tapered in a long curve to its lower end 13, and a plurality of radially extending cuter blades 14 are forged, cast, welded or otherwise made integral with the body and project laterally outthe pilot tooth is a part. face may also be coated with a hard surfacing material,

rm G3 wardly from the body. Three blades are shown but more may be used if desired.

It will be noted that each of the blades 14 projects radially or laterally a substantial distance beyond the exterior surface of the body 10, and also a substantial distance below the lower end 13 of the body.

Each of the blades has at its lower end a pilot blade or tooth section 15 which is in the form of the usual drag type blade or tooth projecting substantially below the lower end 13 of the body and provided with a hard surfacing insert 15a at its lower end providing a hard, tough, wear resistant cutting edge on such face. secured in place on the face of the tooth in the usual manner, by brazing, silver soldering or the like. The three pilot drag teeth shown have their inner edges 16 curved inwardly and downwardly from a point adjacent the lower end of the body 10, and the space between the blades or teeth is adapted to provide a passageway for drilling fluid for washing the formation cuttings from between the blades or teeth. The rear side of each pilot blade or tooth is curved convexly from the rear surface of the blade downwardly toward the lower end of said tooth asindicated at 15b whereby the pilot teeth are relieved be hind their lower ends so as to permit entry of drilling fluid therebehind to aid in boring the pilot hole.

Each of the pilot teeth 15 extends laterally outwardly from its inner face adjacent the longitudinal central axis 'of the bit to a point in substantially vertical alignment with the maximum outer periphery of the body 10 and has a vertically upwardly extending outer face 17 which extends upwardly to a point adjacent the lower end of the body and is disposed substantially midway of the total lateral dimension of the cutter blade'14 of which This upwardly extending outer if desired. From this vertical face the lower end of the outer portion of each of the cutter blades extends downwardly and outwardly in a convex curve 18 to the outermost surface 19 of the cutter blade, whereby a pointed finger 20 is formed on the lower outer end of the outer portion of each of the cutter blades, as clearly shown in Figures 1 and 3. The rear side of each of the fingers 'is curved convexly from the rear surface of the cutter blade downwardly toward the point 25, as indicated at 21, whereby the fingers 20 are rather sharply pointed, and will penetrate the earth formations rapidly. The face 22 and the outer edge 19 of the finger portion of the blade are provided with a coating 23 and 24, respectively, of barium or other hard, wear resistant material, to prevent excessive wear of the blades. If desired, an insert of a high abrasion resistant material, such as tungsten carbide, may be positioned in the point portion 25 of each of the fingers to assure long life.

It will be noted that the lower ends or points 25 of the fingers 20 of the blades terminate in a plane above the lower ends of the pilot teeth 15. Hence, the pilot teeth form a pilothole, and the fingers cut the major portion of the formations. In the dimensions illustrated, the fingers will out about three times as much cross-sectional area as will the pilot teeth 15. Since the fingers are pointed in the manner described, it will readily be apparent that these points will dig into the formations and quickly tear the same loose, and that the curved inner surfaces 18 of the fingers will direct the'formation material torn loose by the finger points 25 toward the center of the hole previously cut away by the pilot teeth 15. Drilling mud, water or other flushing material forced downwardly through the bore 11 of the body and then upwardly exteriorly thereof will carry the cuttings upwardly from The insert is the drillbit blades 14, it will be seen that a relatively soft formation can be dug at a high rate of speed with this drill bit, the points penetrating the formation very rapidly. Also, the outer edges 19 of the blades form reamers and centering guides for the cutting blades and assure that a straight and well sized hole will be dug by the bit.

Obviously, while a pin type connection is illustrated by the external screw threads 12 at theupper end of the body, it"is believed readily apparent that a box type connection having internal screw threads of the usual type may be formed on the upper-end of the body if desired.

Also, the long curved convex taper of the body provides for a'quick pickup of the cuttings from adjacent the blades and provides increased velocity of flow so that the cuttings will move with the rapidly flowingmud readily away from the cutting blades to the surface.

The foregoing description of the invention is explanatory only, and changes in the detailsof the construction illustrated may be made by those skilled in the art, within the scope of the appended claims, without departing from the spirit of the invention.

What I claim and desire to secure by Letters Patent is:

1. A drill bit including: a body having means at one end to secure it to the lower end of a drill string; and three radially extending blades disposed longitudinally of the body and spaced uniformly around the body, each of said blades being vertically straight and having its lower portion reduced in width to provide a pilot blade disposed below the lower end of the body, the lower edge of each pilot blade having a substantially horizontal cutting edge, the outer surface of said pilot blades extending parallel to the axis of the body to a point adjacent the lower end of the body, the lower portion of the blade then extending downwardly and outwardly to a point at the extreme outer edge of the blade, said outer edge of the blade extending vertically parallel to the longitudinal axis of the body and extending laterally a substantial distance from said body, said downwardly and-outwardly curved lower edge surface forming a finger point disposed radially outwardly from the pilot blade and positioned above the lower cutting edge of the pilot blade, said downwardly and outwardly extending portion of the blade forming said finger point being entirely disposed laterally beyond the periphery of said body.

2. A drill 'bit including: a body having means at one end to secure it to the lower end of a drill string; and three radially extending blades disposed longitudinally of the body and spaced uniformly around the body and extending radially a substantial distance beyond said body, each of said blades having its lower portion reduced in width to provide a pilot blade disposed below the lower end of the body, the lower edge of each pilot blade having a substantially horizontal cutting edge, the outer surface of said pilot blades extending parallel to the axis of the body to a point adjacent the lower end of the body,

the lower portion of the blade then extending downwardly and outwardly to a point at the extreme outer edge of the blade, said downwardly and outwardly extending portion of said blade disposed entirely radially outwardly beyond the periphery of said body, said outer edge of the blade'extending vertically parallel to the longitudinal axis of the body, said downwardly and outwardly curved lower edge surface forming a finger point disposed radially outwardly from the'pilot blade and'positioned above the lower cutting edge of the pilot blade, the inner edges of said p'ilot blades being spaced apart.

3. A drill bit including: a body having means at one end to secure it to the lower end of a drill string; and three radially extending blades disposed longitudinally of the body and spaced uniformly around the body, said blades extending radially a substantial distance beyond said body, each of said blades being vertically straight and having its lower portion reduced in width to provide a pilot blade disposed-below the lower end of the body, the lower edge of each pilot blade having a substantially horizontal cutting edge, the outer surface of said pilot blades extending parallel to the axis of the body to a point adjacent the lower end of the body, the lower portion of the blade then extending downwardly and outwardly to a point at the extreme outer edge of the blade, said downwardly and outwardly extending portion of said blade disposed entirely radially outwardly beyond the maximum lateral dimension of said body, said outer edge of the blade extending vertically parallel to the longitudinal axis of the body, said downwardly and outwardly curved lower edge surface forming a finger point disposed radially outwardly from the pilot blade and positioned above the lower cutting edge of the pilot blade, the inner edges of said pilot blades being spaced apart to provide a flow opening therebetween, said body having a longitudinal bore therethrough opening at its lower end onto the flow opening between the pilot blades, said bore providing a substantially unrestricted flow course through saidbody.

4. A drill bit including: a body having means at one end to secure it to the lower end of a well drill string, said body having an axial bore therethrough, said body having its outer surface convexly tapering downwardly from adjacent said securing means to its lower end; and three longitudinally extending blade members projecting radially a substantial distance beyond said body and uniformly spaced circumferentially of said body,-each of said blade members being vertically straight and including: a pilot blade portion extending downwardly below the lower end of the body and having a lateral dimension of'approximately one-half the full lateral dimension of said 'blade member, each of said pilot blade portions having its -longitudinal outer edge extending parallel to the axis of the body and having its inner longitudinal edge flared convexly downwardly, the lower end of each pilot blade portion being substantially horizontal, said inner edges of said pilot blade portions being spaced apart to provide a flow opening therebetween disposed directly below and exposed to fluid flowing from the lower end of the bore of the body; and a finger bit portion having a lateral dimension of the remaining substantially one-half of the lateral dimension of the blade member, said finger bit portion of each blade member being positioned radially outwardly beyond the longitudinal edge of the pilot blade portion and being entirely disposed radially outwardly beyond the maximum crosssectional dimension of said body, said finger bit portion having a substantial point at its lower outer edge and having a surface curved convexly inwardly and upwardly from-said point to the upper end of the longitudinal outer edge of said pilot blade portion, the outer longitudinal edge of said finger bit portion extending substantially parallel to the axis of the body through a major portion of the length ofsaid blade member and then extending inwardly to the exterior of the body at the upper end of its tapered portion, the axial bore through said body providing a substantially unrestricted flow course therethrough.

5. A drill bit including: a body having means. at one end to secure it to the lower end of a well drill string, said body having an axial bore providing a substantially unrestricted flow course therethrough, said body having its outer surface convexly tapering downwardly from adjacent said securing means to its lower end; and three radially projecting longitudinally extending blade members uniformly 'spacedcircumferentially of said body, each ofsaid blade members being vertically straight and including: a pilot blade portion'extending downwardly below the lower end of the body and having a lateral dimension of approximately one-half the full lateral dimensi-on of said blade member, each of said pilot blade portions having its longitudinal outer edge extending parallel tothe axis of the body and having its inner longitudinal edge flared convexly downwardly, the lower end of each pilot blade portion being substantially horizontal, said inner edges of said pilot blade portions being spaced stantially one-half of the lateral dimension of the blade.

member and having a longitudinal dimension greater than its lateral dimension, said finger bit portion of each blade member being positioned radially outwardly beyond the longitudinal edge of the pilot blade portion and being positioned radially outwardly beyond the outer surface of said body, said finger bit portion having a substantial point at its lower outer edge and having a surface curved convexly inwardly and upwardly from said point to the upper end of the longitudinal outer edge of said pilot blade portion, the outer longitudinal edge of said finger bit portion extending substantially parallel to the axis of the body through a major portion of the length of said blade member and then extending inwardly to the exterior of the body at the upper end of its tapered portion, and said pilot blade portion having wear resistant material exposed at its lower edge and along its longitudinal outer edge.

6. A drill bit including: a body having means at one end to secure it to the lower end of a well drill string, said body having an axial bore providing a substantially unrestricted flow course therethrough, said body having its outer surface convexly tapering downwardly from adjacent said securing means to its lower end; and three radially projecting longitudinally extending blade members uniformly spaced circumferentially of said body, each of said blade members being vertically straight and including: a pilot blade portion extending downwardly below the lower end of the body and having a lateral dimension of approximately one-half the full lateral dimension of said blade member, each of said pilot blade portions having its longitudinal outer edge extending parallel to the axis of the body and having its inner longitudinal edge flared convexly downwardly, the lower end of each pilot blade portion being substantially horizontal, said inner edges of said pilot blade portions being spaced apart to provide a flow opening therebetween disposed directly below and exposed to fluid flowing from the lower end of the bore of the body; and a finger bit portion having a lateral dimension of the remaining substantially one-half of the lateral dimension of the blade member and having a longitudinal dimension greater than its lateral dimension, said finger bit portion of each blade member being positioned radially outwardly beyond the longitudinal edge of the pilot blade portion and being positioned radially outwardly beyond the outer surface of said body, said finger bit portion having a substantial point at its lower outer edge and having a surface curved convexly inwardly and upwardly from said pointto the upper end of the longitudinal outer edge of said pilot blade portion, the outer longitudinal edge of said finger bit portion extending substantially parallel to the axis of the body through a major portion of the length of said blade member and then extending inwardly to the exterior of the body at the upper end of its tapered portion; said finger bit portions having their rear surfaces icurved convexly upwardly from said point to substantially the plane of the lower end of the body.

7. A drill bit including: a body having means at one end to secure it to the lower end of a well drill string,- said body having an axial bore providing a substantially unrestricted flow course therethrough, said body having its outer surface convexly tapering downwardly from adjacent said securing means to its lower end; and three radially projecting longitudinally extending blade members uniformly spaced circumferentially of said body, each of said blade members being vertically straight and including: a pilot blade portion extending downwardly below the lower end of the body andhaving a lateral dimension of approximately one-half the full lateral dimension of said blade member, each of said pilot blade 6, portions having its longitudinal outer edge extending parallel to the axis of the body and having its inner longitudinal edge flared convexly downwardly, the lower end of each pilot blade portion being substantially horizontal, said inner edges of said pilot blade portions being spaced apart to provide a flow opening therebetween disposed directly below and exposed to fluid flowing from the lower end of the boreof the body; and a finger bit portion having a lateral dimension of the remaining substantially one-half of the lateral dimention of the blade member and having a longitudinal dimension greater than its lateral dimension, said finger bit portion of each blade member being positioned radially outwardly beyond the longitudinal edge of the pilot blade portion and being positioned radially outwardly beyond the outer surface of said body, said finger bit portion having a substantial point at its lower outer edge and having a surface curved convexly inwardly and upwardly from said point to the upper end of the longitudinal outer edge of said pilot blade portion, the outer longitudinal edge of said finger bit portion extending substantially parallel to the axis of the body through a major portion of the length of said blade member and then extending inwardly to the exterior of the body at the upper end of its tapered portion; said finger bit portions having their rear surfaces curved convexly upwardly from said point to substantially the plane of the lower end of the body, and said pilot blade portions having their rear surfaces curved convexly upwardly from the lower edge of their face.

8. A well drill bit including: a body having means at one end to secure it to the lower end of a well drill string and having an axial bore providing a substantially unstricted flow opening therethrough; three elongated cutting members extending substantially radially from the surface of said body, said cutting members being vertically straight and equidistantly disposed about the longitudinal axis of said body and terminating in a longitudinal outer cutting edge position defining the diameter of a hole to be drilled, said cutting members extending below the lower end of said body, the inner edges of the portions of said cutting members extending below said body being spaced apart to provide a flow opening therebetween disposed directly below and exposed to fluid flowing fromthe lower end of the bore of said body, said spaced apart inner edges of said cutting members being flared convexly downwardly; each cutting member having a leading planar surface portion extending substantially radially from the longitudinal axis of said body and terminating in said longitudinal outer cutting edge portion, each of the cutting members having a lower cutting end edge portion extending substantially radially from the inner edge of each of said members and intersecting a longitudinal intermediate cutting edge portion, said longitudinal intermediate cutting edge portions being disposed approximately midway between the inner edges and the longitudinal outer cutting edge portions and extending substantially parallel to the axis of said body upwardly to a plane approximately coincident with the lower end of said body; and a downwardly extending cutting finger on each cutting member disposed substantially radially outwardly of said intermediate longitudinal cutting edge, the lower ends of said fingers terminating in a plane disposed above the lower cutting end edge portions of said cutting members but below the upper ends of said intermediate longitudinal cutting edges, the outer edges of said fingers coinciding with the longitudinal outer cutting edges of said cutting members and the inner edges of said fingers being curved convexly downwardly from the upper ends of said intermediate longi tudinal cutting edges whereby the lower ends of each of said fingers are formed with a point disposed on said outer longitudinal cutting edges, said fingersbeing disposed entirely radially outwardly of said body, the longitudinal dimensions of said fingers being greater than the lateral dimensions thereof; the rear surfaces of said 7 fingers being curved convexly upwardly from said points 1,775,774 to substantially the plane of the lower end of said body. 2,011,158

1 5 5 2,615,684 References Cited in the file of this patent 2,656,153 UNITED STATES PATENTS 5 2,776,818 1,326,506 Humason Dec; 20, 1919 2783973 1,535,572 Burton Apr. 28, 1925 1,587,266 Zublin June 1, 1926 8 Murphy Sept. 16, 1 930 Pearce Aug. 13; 1935 Hawthorne Oct. 28, 1952 White Oct. 20, 1953 Walker Jail. 8, 1957 Hawthorne et al Mar. 5, 1957 

